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  • 1985-1989  (1,253)
  • 1970-1974
  • 1860-1869
  • 1987  (1,253)
  • Analytical Chemistry and Spectroscopy  (1,177)
  • Ultrastructure
Material
Years
  • 1985-1989  (1,253)
  • 1970-1974
  • 1860-1869
Year
  • 1
    ISSN: 1432-2285
    Keywords: Cambial activity ; Frost hardiness ; Phenology ; Salix ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The ultrastructure of cells in the cambial region of Salix dasyclados Wim. (clone 78056) was studied during the development of winter hardiness and the onset of cambial activity in spring. Plants were grown at relative growth rates (RG) of 8% and 12% respectively, resulting in different nitrogen content in the stems. Frost hardiness of the plants was estimated by standardized freezing tests. Plants with a higher nitrogen status ceased growth later and started re-growth earlier in spring than plants with lower nitrogen content. Differences in ability to withstand low temperatures during autumn and spring were found between plants grown in the two nutrient treatments. During the development of frost hardiness in the autumn, the number of meristematic cells in the cambial region decreased. The cessation of meristematic activity was accompanied by cell wall thickening and ultrastructural changes in the cells. Frost hardiness increased from the ability to survive -6° C in October to survival of -80° C at the beginning of December. From November to February the cambial region comprised a layer of 2–3 thick-walled cells with conspicuous ultrastructural features. Starch accumulated in plastids in September, decreased during November to March and then increased again in accordance with changes of frost hardiness. Onset of cambial activity began between the end of March and the beginning of April, as shown by increased vacuolization of meristematic cells and mitotic activity. By April, the starch content had increased and lipolysis was observed. Frost hardiness had decreased, and plants with low and high nitrogen content were able to survive -15° C and -10° C, respectively. After budburst, all axillary shoot parts were damaged at temperatures below-3° C.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 411 (1987), S. 93-98 
    ISSN: 1432-2307
    Keywords: Gliomatosis cerebri ; Brain tumour ; Ultrastructure ; Glial cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural features of five biopsies of gliomatosis cerebri (GC) are described. Four main types of tumour cells are seen: anaplastic astrocytes poor in organelles with a variable amount of glial microfilaments; atypical oligodendrocytes with scanty cytoplasm in which microtubules are present; intermediate forms with aboundant cytoplasm rich in organelles, with microtubules and microfilaments; and small cells with round nuclei and a very scanty rim of cytoplasm. In two cases several concentrically folded cytoplasmic lamellae of glial processes were arranged either around themselves or around the perikaryon of other cells. This ultrasructural study indicates that GC is a neoplastic process of small undifferentiated elements, transitional forms of astroglia (to oligodendroglia) and anaplastic cells of astrocytic origin in all stages of development.
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  • 3
    ISSN: 1432-2307
    Keywords: Soft tissue neoplasm ; Sarcoma ; Rhabdoid cell ; Rhabdoid tumor ; Ultrastructure ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report the occurrence of rhabdoid cells in several specified soft tissue sarcomas of round cell variety. The rhabdoid cells had an acidophilic cytoplasm containing a globular perinuclear inclusion and were characterised ultrastructurally by the presence of aggregates of 10 nm intermediate filaments. These filaments contained both cytokeratin and vimentin, as demonstrated immunohistochemically. Extensive sampling of soft tissue sarcomas revealed the presence of such cells in different types of soft tissue round cell sarcomas as follows: 12 of 13 cases of epithelioid sarcomas, 8 of 13 synovial sarcomas (composed predominantly of round cells), 6 of 20 extraskeletal myxoid chondrosarcomas and 4 of 4 round celled malignant mesotheliomas. We wish to stress that the appearance of rhabdoid cells is not a monopoly of one particular type of tumour.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 410 (1987), S. 317-326 
    ISSN: 1432-2307
    Keywords: “Primary” endothelial cilia ; Endothelial centrioles ; Human atherosclerosis ; Ciliary transitional fibers ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary “Primary” cilia were present in the endothelial cells of human aortic fatty dots and streaks but not in those of normal intima. They had the features of cilia of the “9+0” axonemal configuration observed in many other cells. A lateral foot process and transitional fibers “anchored” the ciliary basal body in the cytoplasm, but rootlets were not identified in material examined. Ladder-like configurations interconnected the two centrioles (=diplosome) of control endothelium. The “primary” cilia of endothelium differed from those of the rudimentary type observed in smooth muscle cells in similar lesions of man, but shared many features with cilia of those present in experimental atherosclerosis in rabbit. Cilia were rarely described in vascular endothelium. It is believed that, to date, they were not reported to occur in normal or pathological arteries in man. It is being stressed that whereas the significance of these unusual organelles remains uncertain, their widespread occurrence may indicate that their role is more important than was believed previously, and they should cease being a curiosity only.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 410 (1987), S. 93-96 
    ISSN: 1432-2307
    Keywords: Heterogeneity ; Ultrastructure ; Colonic carcinoid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This report describes a colonic carcinoid tumor in which three, and possibly four, distinct cell types are distinguishable on the basis of their ultrastructure and granule morphology. These cell types closely resemble the normal endocrine cells of the large bowel, both in appearances and in relative frequency. The mixed composition of this tumor may have arisen either by parallel differentiation of distinct cell types, or by sequential maturation of one cell type.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 412 (1987), S. 119-125 
    ISSN: 1432-2307
    Keywords: 16,16-dimethyl prostaglandin E2 ; Aspirin ; Tight junctions ; Stomach ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The canine gastric epithelium was exposed to solutions containing 20 mM aspirin and 20 mM aspirin + 30 µg/kg 16,16-dimethyl prostaglandin E2 (dmPGE2) for periods of three and forty minutes. No macroscopic hemorrhagic lesions were seen. Light microscopically, surface lesions were reduced from 10 percent (aspirin alone) to 2.5% (aspirin+dmPGE2). However, dmPGE2 does not appear to attenuate aspirin induced tight junction alterations. Discontinuities in the apical occluding complexes, hyperplastic tight junctions and stand number variability were documented in freeze frature replicas of aspirin as well as aspirin+ dmPGE2 treated dog stomachs. The results of these experiments would seem to suggest that 30 µg/kg dmPGE2 does not prevent aspirin induced damage to the tight junctions of the canine gastric epithelium or enhance their repair.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 411 (1987), S. 561-568 
    ISSN: 1432-2307
    Keywords: Psammous desmo-osteoblastoma ; Ultrastructure ; Osteonectin ; Bone tumours ; Fibro-osseous lesion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fibro-osteo-cemental lesions of the jaw bones are a heterogeneous group of diseases which present problems in classification. Psammous desmo-osteoblastoma is one of four newly proposed entities (Makek 1983) and has until now been characterized by its light microscopic, clinical and radiological features. On electron microscopy this tumour exhibits fibroblastic (preosteoblastic), osteoblastic and osteocytic cells and a globular mineralization unlike the mineralization of the psammoma bodies. Immunohistological investigations with anti-osteonectin, a bone specific protein linking mineral to collagen, showed positive intracellular staining in all tumour cells and extracellular staining in the osteoid. The psammoma bodies were, however, not stained. These results confirm the view of the osteogenic histogenesis of psammous desmo-osteoblastoma, with an osteogenic differentiation of the tumour cells, bone formation and association of psammoma bodies which are not of bone origin. This combination of findings supports the view that psammous desmo-osteoblastoma represents a new and distinct entity occuring in desmal preformed cranio-facial bones which should be incorporated in a revised WHO-classification.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 411 (1987), S. 293-298 
    ISSN: 1432-2307
    Keywords: Ectocervix ; Serotonin cells ; Calcitonin cells ; Ultrastructure ; Transitional epithelium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A systematic study of endocrine cells in the ectocervix was carried out using histochemical, immunohistochemical and ultrastructural techniques. Serotonin and calcitonin immunoreactive cells were demonstrated in this site. Serotonin and calcitonin immunoreactivities were coexpressed in the same endocrine cell. These distinctive cells were encountered in two main morphological varieties of ectocervical epithelium. Normal-appearing stratified squamous epithelium contained only very rare serotonin and calcitonin cells. In contrast, endocrine cells were fairly abundant in a specific epithelium termed “transitional-like”. This type of epithelium was not only confined to the transformation zone but could also extend onto the portio as far as the vaginal cut margin. In some cases, transitional-like epithelium bore morphological resemblance to urothelium. In other cases, it could be regarded as basal cell hyperplasia or immature squamous metaplasia. Of interest, serotonin and calcitonin cells have been well-documented as normal inhabitants of some other non-squamous epithelia, such as urothelium or pseudostratified columnar epithelium. Therefore, it is suggested that certain ectocervical epithelia show some similarities to urothelium, in respect of their morphological appearance and endocrine profile. Further investigations using more objective and specific markers of urothelial cells are needed to assess the exact degree of homology connecting all these types of epithelium.
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  • 9
    ISSN: 1432-2307
    Keywords: Human heart ; Papillary muscle ; Myocardial hypertrophy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An ultrastructural study using various electron microscopical techniques has been conducted on biopsy material from the hypertrophied papillary muscle of the human heart. About 75% of the myocardial cells were classified as hypertrophic with diameters ranging from 15 εm to 53 εm. The increased cell diameter appeared to be the result of an elevated amount of mitochondria and contractile material. The hypertrophied myocytes displayed a general ultrastructural organization in many ways similar to that of the normal sized myocytes. However, the former cells were characterized by focal deposits of excess laminar coat material and abnormal Z-band patterns as well as of multiple intercalated discs. The preferential sites for the production of new sarcomere elements appeared to be in the subsarcolemmal and intercalated disc regions. Adjacent myocardial cells were interconnected by collagen bundles, and, by an elaborate collagen-fibril-microthread-granule lattice. The surface folds were linked to each other by surface cables, which probably constituted a separate category of extracellular material of unknown function. Intramembranous particles were abundant in the sarcolemma proper but scarce in the membranes of the sarcoplasmic vesicles. Such particles were also observed in the lipofuscin granular membrane and in the membranes surrounding the lipid droplets. A framework of transverse cytoskeletal filaments interconnected the Z-bands of adjacent myofibrils and anchored the contractile material to the sarcolemma as well as to the nucleus. A large and lobulated nucleus containing well developed nucleoli together with an abundance of sarcoplasmic free and membrane-attached ribosomes, were interpreted as morphological signs of enhanced synthetic activity in the hypertrophied cell. Degenerative phenomena on the other hand were confined to lysosomal degeneration of worn-out cell constituents that were manifested by the numerous lysosomes and aggregates of lipofuscin granules. Abnormal Z-band patterns as seen in the present material were interpreted as an initial stage in the formation of new contractile elements.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 411 (1987), S. 267-273 
    ISSN: 1432-2307
    Keywords: Corticotropic adenoma ; Ultrastructure ; Pituitary oncocytoma ; Choroid Plexus carcinoma ; Mitochondrial morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The report documents a silent, oncocytic, ACTH-producing ectopic anterior pituitary tumour in a 6-year-old boy. The invasive intrahemispheric neoplasm had no connection with the pituitary gland, the sella turcica or the sphenoid sinuses. The apparent similarities existing between this tumour, some choroid plexus carcinomas and steroid-producing neoplasms are discussed.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 411 (1987), S. 283-291 
    ISSN: 1432-2307
    Keywords: Tumor invasion ; Ultrastructure ; Desmoplasia ; Squamous cell carcinoma ; Lung parenchyma ; Basal lamina
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using ultrastructural methods we studied the interaction of tumour cells and lung parenchyma in deep areas (i.e., more than about 3 mm from the tumour surface) of 50 bronchogenic squamous cell carcinomas. The tumour periphery, studied previously, had shown organized associations of tumour cells and lung epithelial cells and a surprising lack of invasion of non-epithelial tissue compartments. The deeper areas, where the tumour cells and the lung parenchyma had been in contact for longer periods, consisted of irregular groups of tumour cells and desmoplastic stroma which was very similar to granulation tissue. The deeper areas also contained many intact lung epithelial cells, arranged in compressed and distorted alveolar structures. Where non-neoplastic epithelial cells and tumour cells had direct contact, they formed common junctional complexes and basal laminae. In part of the tumours, the cells were largely devoid of a basal lamina. However, in most instances a continuous basal lamina surrounded every tumour cell group studied, even when these formed irregular strands or seemed to be completely isolated.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 412 (1987), S. 175-182 
    ISSN: 1432-2307
    Keywords: Appendix ; Colorectal neoplasm ; Carcinoid ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The clinicopathological features of six appendix and five bowel tumours with features of the so-called ‘goblet cell carcinoid’ are described. By light microscopy, these tumours were composed predominantly of mucous cells, together with variable proportions of endocrine and Paneth cells. Immunohistochemical and ultrastructural study confirmed this impression and no amphicrine cells were seen. The clinical course of all cases arising in the bowel, and three out of six appendix tumours was characterised by an aggressive behaviour with the development of widespread lymphatic and often intraperitoneal metastasis, but liver metastasis occurred in only one instance. We conclude, both from this study and from a review of the literature, that the ‘mixed crypt cell carcinoma’ forms a distinct clinicopathological entity justifying separate classification from adenocarcinoma and carcinoid tumour.
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  • 13
    Electronic Resource
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    Springer
    Archives of gynecology and obstetrics 240 (1987), S. 137-146 
    ISSN: 1432-0711
    Keywords: Preovulatory granulosa cells ; Call-Exner body ; Fibrin ; Human ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of preovulatory granulosa cells may be distinct in follicles containing competent as opposed to non-competent oocytes. To test this assumption, granulosa cells were looked for in 36 follicular fluid aspirates from 8 patients taking part in an in vitro fertilization and embryo transfer program. Granulosa cells were absent from 16 aspirates and present in 20. Both aspirate types contained oocytes able to develop in culture. Granulosa cells were subdivided into three developmental stages. Stage 1 (5% of aspirates) showed proliferating cells, while stage 2 (60% of aspirates) and 3 (35% of aspirates) cells were in the preluteinization stage. These cells were recognizable by their number of lipid droplets and differentiated according to possession of a rough (stage 2) or smooth (stage 3) endoplasmic reticulum. Luteinization did not occur in these cells. All stages displayed desmosomes, gap junctions, and annular junctions. The structure of Call-Exner bodies and of fibrin deposits were unexpected findings. Our study indicates that there is no correlation between the previously used morphological parameters of granulosa cells and oocyte maturity.
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  • 14
    ISSN: 1432-0738
    Keywords: Silver toxicity ; Cultured macrophages ; Cell death ; Ultrastructure ; Lipid peroxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of silver on cultured mouse peritoneal macrophages were examined by estimation of cell survival and by light and electron microscopy. Additon of silver lactate to the culture medium at final concentrations of 40 and 80 μM resulted in coagulation necrosis and rapid cell death. At lower concentrations cell structure appeared normal. However, the rate of cell death at 20 μM silver lactate was increased as compared to controls. Silver, visualized by physical development/autometallography, was invariably located in lysosomes. The production of malondialdehyde in mouse liver of silver-treated mice as compared to controls was also examined. This lipid peroxidation product had increased to the same amount in animals treated with silver for either 3 days or with only one silver injection 4 h before examination. This study has demonstrated that silver affects viability and structure of cultured macrophages, possibly due to induction of lipid peroxidation, as demonstrated to occur in the liver of silver-exposed mice.
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  • 15
    Electronic Resource
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    Acta neuropathologica 74 (1987), S. 307-312 
    ISSN: 1432-0533
    Keywords: Ganglioglioma ; Neuronal degeneration ; Ultrastructure ; Brain stem ; Brain tumor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A brain stem ganglioglioma in a 9-year-old female was examined ultrastructurally. The constituent neuronal (ganglion) cells displayed various ultrastructural features of neuronal degeneration including Hirano, Lafora and zebra bodies, inclusion-like aggregates of neurofilaments and large dilatations of rough endoplasmic reticulum. Although similar observations have been reported in peripheral neuronal tumors, this is the first reported occurrence in ganglioglioma, an uncommon tumor in the central nervous system. The coincidence of these alterations in the present tumor appeared to be of great interest, however, their exact etiology remained uncertain.
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  • 16
    ISSN: 1432-0533
    Keywords: Intermediate filaments ; Glial fibrillary acidic protein (GFAP) ; Vimentin ; Ultrastructure ; Glioma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Glial filaments contain vimentin and glial fibrillary acidic protein (GFAP). The question of how glial filaments change morphologically according to the expression of vimentin and/or GFAP has remained unclear. In this study, immunohistochemical and ultrastructural examinations were performed on the subcutaneously transplanted tumors of two clones (F6B3 and G10A10) derived from a mouse glioma. F6B3 tumor expressed GFAP and vimentin in large quantities. G10A10 tumor expressed plenty of vimentin but only a little of GFAP. Ultrastructurally, F6B3 tumor contained abundant cytoprocesses in most of which numerous intermediate filaments (IFs) were arranged in a parallel array. On the other hand, only a small number of the processes were seen in G10A10 tumor, which showed a few IFs arranged either randomly or sparsely in the processes. Both tumors commonly had the IFs accompanied by visible sidearms, but there was a difference in that the smooth and firm IFs were confined to part of F6B3 tumor. Thus, the comparison made between the two models presented differences in the content, arrangement and morphology of IFs, as well as in the manner of GFAP expression, suggesting correlation between these differences.
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  • 17
    Electronic Resource
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    Acta neuropathologica 73 (1987), S. 281-286 
    ISSN: 1432-0533
    Keywords: Teratoma ; Nervous tissue ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of the nervous tissue in a benign ovarian teratoma is described. This tissue was organized into areas having both “meningel” and “ependymal” surfaces, between which were found astrocytes, ependymal cells, neurones with synapses and microglia. These cells all had ultrastructural similarities to their normal counterparts in the nervous system. In addition, some signs of degenerative change — due possibly to the abnormal location of the nervous tissue — were observed. Oligodendrocytes and myelin were absent, possibly because of vascular insufficiency.
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  • 18
    Electronic Resource
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    Springer
    Acta neuropathologica 75 (1987), S. 147-155 
    ISSN: 1432-0533
    Keywords: Esthesioneuroepithelioma ; Ultrastructure ; Immunohistochemistry ; Neurofilament protein (NFP) ; Keratin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of esthesioneuroepithelioma was investigated ultrastructurally and immunohistochemically, using antibodies against neurofilament protein (NFP), glial fibrillary acidic protein (GFAP), keratin, neuron-specific enolase (NSE), S-100 protein (S-100), and tyrosine hydroxylase (TH). The tumor initially manifested as an epidural mass in the anterior cranial fossa in a 64-year-old man, and about 31/2 years later, autopsy further revealed extensive metastases to the lymph nodes of the neck and thoracic cavity. In the cranial and nasal cavities, the tumor was composed of fairly uniform, ill-defined cells arranged in nests which were surrounded by a fibrovascular stroma. These histological features were reproduced in the metastatic tumor nodules with frequent occurrence of tubular arrangements of the tumor cells. Ultrastructurally, two different cell types were well recognized by their characteristic morphological features, which were reminiscent of sensory neurons and sustentacular cells of the olfactory epithelium. No dense-cored secretory granules were observed in the tumor cells. Immunohistochemically, the tumor showed a variable number of cells positive for NFP, keratin, NSE and S-100. NFP was present in a relatively small number of cells, which were found diffusely in the nests. Keratin was observed in the cells mainly located at the periphery. NSE-positive cells tended to form irregular clusters in the center. A few S-100-positive cells were found, without any particular arrangement. These findings indicated that the present tumor, which actually arose in the superior nasal cavity, consisted of cells differentiating in at least two distinct directions, neuronal and epithelial, and strongly suggested that the tumor was of true olfactory epithelium origin, or more precisely, derived from the bipotential, undifferentiated basal cells of this epithelium.
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  • 19
    ISSN: 1432-0568
    Keywords: Serotonin ; Substantia nigra ; Mammals (rat, cat, Macaca fuscata) ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of serotonin-containing nerve fibers in the substantia nigra of the rat, cat and monkey was studied with a highly sensitive peroxidase-antiperoxidase immunohistochemical method. Serotonin fibers in the substantia nigra of all species consisted of fine varicose fibers and formed a fine network. In the zona compacta of all species, serotonin fibers were sparsely distributed. In the zone reticularis of the rat and cat, these fibers were densely distributed and their distributional pattern was almost uniform, while in the monkey such fibers were unevenly distributed and high and low dense areas were intermingled. In the pars lateralis of all species, serotonin fibers were diffusely distributed, and the distributional density was much higher in the cat and monkey than in the rat. Immunoelectron-microscopic studies further revealed that a majority of the labeled varicosities in the rat substantia nigra were in close apposition to peridendritic axon terminals and were also free in the neuropil; occasionally they exhibited symmetrical synapses of “en passant” type with non-immunoreactive dendrites or somata. Our results support a functional significance of serotonergic regulation of the substantia nigra in mammals.
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  • 20
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    Anatomy and embryology 176 (1987), S. 41-44 
    ISSN: 1432-0568
    Keywords: Bovine ; Oocyte maturation ; Meiosis ; Gap junction ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cumulus-oocyte complexes were obtained from cows by aspiration of small (1–6 mm in diameter) antral follicles after slaughter. Complexes with a compact multilayered cumulus investment were cultured and processed for transmission electron microscopy after different periods of culture including a 0 h control group. In 0 h control oocytes the cumulus cells had numerous projections which penetrated the zona pellucida and established gap junctions with the oolemma. A partial loss of these junctions was noticed as an early event of oocyte maturation occurring within the first 3 h of culture. A low frequency of gap junctions was maintained until 12–18 h of culture where the junctional contact was completely disrupted. This decrease in intercellular communication was parallelled by resumption of oocyte meiosis.
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  • 21
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    Anatomy and embryology 176 (1987), S. 35-40 
    ISSN: 1432-0568
    Keywords: Bovine ; Oocyte maturation ; Meiosis ; Nucleus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cumulus-oocyte complexes were obtained from cow ovaries by aspiration from small (1–6 mm in diameter) antral follicles after slaughter. Complexes with a compact multilayered cumulus investment were cultured and subsequently processed for electron microscopy after various periods of culture. By morphological criteria the oocytes could be divided into the following sequence of meiotic stages. The oocyte nucleus I stage was characterized by a spherical nucleus located peripherally in the ooplasm while undulation of the nuclear envelope and initial chromatin condensation was seen at the oocyte nucleus II stage. The oocyte nucleus breakdown stage was characterized by formation of long slender projections from the nuclear envelope in which the envelope doubled back on itself, appearance of dense areas and haphazardly oriented microtubules in the nucleus, marked condensation of the chromatin, and dissolution of the nuclear envelope into irregular vesicles and tubules. The condensed chromatin I stage was characterized by the location of condensed chromatin configuration and uniformly oriented microtubules in a dense area peripherally in the ooplasm while the final condensed chromatin II stage was characterized by a gradual invasion of condensed chromatin configurations into a dense area combined with the presence of the first polar body in the perivitelline space.
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  • 22
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    Archives of dermatological research 279 (1987), S. 459-464 
    ISSN: 1432-069X
    Keywords: All-trans retinoic acid ; Epidermal cells ; Ultrastructure ; Differentiation ; Stratification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of all-trans retinoic acid on human epidermal cell cultures were studied using ultrastructural techniques. Differentiation and stratification were reduced in retinoic acid treated epidermal cells. Treated cells developed a rounded appearance and seemed to contain more granules and vacuoles than usual. Desmosomes were not found in treated cells.
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  • 23
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    Acta neuropathologica 73 (1987), S. 400-402 
    ISSN: 1432-0533
    Keywords: Ultrastructure ; Ependyma ; Experimental hydrocephalus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary New ultrastructural alterations of the ependymal cells in the altered container model of experimental feline hydrocephalus are described. These include half desmosomes and a basal lamina on the apical surface of the ependymal cells, punctate adhesion-like structures between intraventricular mononuclear cell and the apical surface of the ependymal cells and unusual distortion of the ependymal cells. The significance of these previously unreported morphological alterations is unknown.
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  • 24
    ISSN: 1432-0533
    Keywords: Brain ; Global ischemia ; Ultrastructure ; Ionic changes ; Ca
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A time course of tissue ionic changes, and their relation to ultrastructural findings during reperfusion following a 15-min global ischemic brain insult was studied in a dog model. Parietal cortex was analyzed for Ca, Na, K, Mg and Fe in controls and after 10 min, 2, 4, and 8 h of reperfusion. After 8 h of reperfusion, the mean values (μmol/g tissue wet wt.) for Ca (control=1.43, 8 h=2.76) and Na (control 60.4, 8 h=107.4) doubled and K (control=90.4, 8 h=48.5) decreased to half that of the control. Ultrastructural studies and subcellular localization of calcium in parietal cortex of in situ-fixed brains after 8 h showed cortical neurons with clumping of nuclear chromatin, dilatation of endoplasmic reticulum and disruption of plasma membranes. Large amounts of electron-dense precipitates of calcium were present within dilated astrocytic processes, synaptic vesicles, cytoplasm of edematous dendrites and mitochondria. Cortical neurons from postischemic dogs without reperfusion showed only slight chromatin clumping and edema of astrocytic processes, but no calcium accumulation. The large ionic shifts noted between 4 and 8 h of reperfusion, indicate a progressive inability of the cells to maintain normal transmembrane gradients of these ions and may reflect a membrane destructive process, as demonstrated ultrastructurally at 8 h. Enhanced calcium entry into the neuron during reperfusion appears to be a part of the cytotoxic mechanism leading to neuronal necrosis.
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  • 25
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    Anatomy and embryology 175 (1987), S. 399-410 
    ISSN: 1432-0568
    Keywords: Implantation ; Marmoset ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural morphology of the initial stages of implantation in the marmoset monkey (Callithrix jacchus) was studied in pregnant monkeys at known time intervals after ovulation. The earliest samples, obtained 13 days after ovulation, displayed both cytotrophoblast and syncytiotrophoblast. The cytotrophoblast was restricted to the blastocoel, whilst syncytiotrophoblast intruded to the endometrial basal lamina. At later stages, days 16 and 19 after ovulation, both cytotrophoblast and syncytiotrophoblast had extended laterally around the uterus, and the syncytiotrophoblast also extended deeper into the maternal tissnes. The mesoderm layer was first discernible at 19 days after ovulation. At 23 days after ovulation the syncytiotrophoblast surrounded the maternal blood vessels entirely. In this study syncytiotrophoblast was not observed to breach the maternal blood vessels, even at 31 days after ovulation. Early cytotrophoblast columns could be seen at 31 days after ovulation. The endothelial cells lining the maternal blood vessels displayed hypertrophy from the earliest stages (day 13) onwards, although a true decidual response was only observed in samples of 23 and 31 days after ovulation.
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    Anatomy and embryology 177 (1987), S. 131-138 
    ISSN: 1432-0568
    Keywords: Capillaries ; Tooth pulp ; Tight junctions ; Odontoblasts ; Ultrastructure ; Mineralisation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The relative roles of capillaries and odontoblasts in the process of dentinogenesis and in pulp reactions to trauma and pathology are not clear. Contributing to the problem is the paucity of information on odontoblast —capillary relationships and tight junctions between odontoblasts. Using light microscopy the capillaries have now been examined in semithin transverse sections of perfusion fixed teeth at different positions in the long axis from the apical foramina to the pulp horns. Odontoblastic capillaries were prominent in the coronal and middle regions of canines and present at the same levels of incisors. In the pulp horns and just coronal to the pulp horns capillaries were all subodontoblastic but near the apex there were also a few odontoblastic capillary profiles. Transmission electron microscopy on ultrathin sections revealed that a high proportion of middle and coronal odontoblastic capillary profiles were fenestrated but subodontoblastic profiles coronal to the pulp horns were the most fenestrated. In a search for tight junctions in ultrathin sections some typical strands were observed between odontoblasts. The difficult of obtaining the latter evidence was explained by the cellular arrangement of the odontoblasts which differed markedly from an ideal parallel, apically coplanar arrangement. The results question the possibility that there is a direct exchange of materials between pulp capillaries and dentine in teeth of limited growth and provide a baseline for future experiments to test the permeability of the odontoblast layer.
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  • 27
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    Anatomy and embryology 177 (1987), S. 91-96 
    ISSN: 1432-0568
    Keywords: Ultrastructure ; Human egg ; Human embryo ; Cleavage embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A two-cell human embryo recovered from the Fallopian tube 82 h following the LH peak in plasma and 37 h after a single episode of intercourse was examined by transmission electron microscopy. At the time of recovery the embryo was denuded of cumulus cells, and both the zona pellucida and the two adjoining blastomeres were intact. The finding of two polar bodies in the perivitelline space, two nucleated blastomeres and remnants of the fertilizing sperm tail within the cytoplasm of one of them, were considered as evidences that the embryo was normally fertilized. Among the most compicuous features found were the presence of very distinct desmosome-like structure between blastomeres, and the cytoplasmic cell organelles distribution in three areas referred as: a sub-cortical, a middle and a perinuclear bands. An outstanding feature was the extensive blebbing of the nuclear envelope. In general, the features seem to correspond to a normally developing two-cell embryo undergoing cleavage at a normal rate.
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    Anatomy and embryology 177 (1987), S. 147-152 
    ISSN: 1432-0568
    Keywords: Atrial myocardium ; Vagotomy ; Monkey ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of the atrial myocardium in the monkey (Macaca fascicularis) was studied after bilateral cervical vagotomy and survival times of 1, 3, 5, 7, 10, 21 and 28 days. During the first week after vagotomy, a few atrial cells showed a reduction in the sarcoplasm, crowding of the myofibrils, peripheral dispersion and reduced intercristal density of the mitochondria and increased sarcoplasmic reticulum and glycogen particles. In some profiles, there was increased electron density and granularity at the I bands and the intercalated discs. The number of such affected cells increased in the subsequent days such that by 21 to 28 days about 50% of the cells were estimated to be affected. During the latter stages further changes included, the degradation of the myofilaments and increased electron density, disorganisation and disintegration of the digital extensions at the intercalated discs. Throughout the experiments there was a leucocytic infiltration, more evident in the longer survival times.
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  • 29
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    Anatomy and embryology 175 (1987), S. 467-475 
    ISSN: 1432-0568
    Keywords: Mouse spermiogenesis ; Constitutive heterochromatin ; Nucleolus organizing regions ; Fluorochrome ; Staining ; EM silver staining ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this study, the selective fluorochrome staining of constitutive heterochromatin and a specific ultrastructural silver-staining of nucleolar material (i.e., the nucleolus organizing regions) were undertaken to be used as indicators for the chromosomal arrangement during mouse spermiogenesis. Since in mice all somatic chromosomes are telocentric and the constitutive heterochromatin and nucleolar organizing regions are closely associated to the centromeres, this combination of techniques provided for the first time ultrastructural evidence 1) for the dispersion of the constitutive heterochromatic chromocentre and a centrifugal migration to the postacrosomal portion of the nuclear envelope where constitutive heterochromatin seems to mediate the assembling of microtubules in the so-called manchette. As elongation continues, the constitutive heterochromatin migrates back into central position and forms the “focous of earlier condensing chromatin”, which initiates further chromatin condensation. 2) The fate of the nucleolus during spermiogenesis could also be further clarified: The nucleolus is first associated with the chromocentre, but starts to disintegrate during elongation phase. However, argyrophilic remnants are still visible in the centre of the nucleus, pointing to an ongoing transcriptional activity. When they final disappear, they leave behind “nuclear vacuoles” in the dense chromatin mass of the mature sperm nucleus.
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  • 30
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    Anatomy and embryology 176 (1987), S. 231-237 
    ISSN: 1432-0568
    Keywords: Embryonic chick heart ; Interventricular septum ; Mesenchymal tissue ; Endocardial activation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Light and electron microscopic studies of frontal and sagittal sections of embryonic chick hearts (Stages 25, 28–29), reveal mesenchymal tissue in the cephalic portion of the interventricular septum. The endocardium of this cephalic portion contains reoriented and invaginated cells with pseudopodia; in addition there are cells immediately subjacent to the endocardium. Similar cellular events take place during the formation of mesenchymal tissue in the atrioventricular and conotruncal regions. In these regions the mesenchymal tissue originates by means of an endocardial activation process. The structural characteristics of the formation of the cephalic portion of the interventricular septum suggest that local mesenchymal tissue is contributed by the endocardium. However, based upon the close anatomic relationship observed by us between the mesenchymal tissues of the atrioventricular canal, conotruncal region and the cephalic portion of the interventricular septum; we do not discard a contribution by migration of cells from atrioventricular and conotruncal regions to the interventricular septum.
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    Anatomy and embryology 176 (1987), S. 281-294 
    ISSN: 1432-0568
    Keywords: Myotendinous junction ; Human growth ; Skeletal muscle ; Tendon ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The myotendon junction of human paravertebral skeletal muscle was studied by light and electron microscopy. Transverse and longitudinal sections of myotendinous regions of normal multifidus muscles were examined at three chronological stages from birth to maturity. Variations in the appearance of surface extensions at the terminal ends of muscle fibers consisted of brush-like evaginations at birth and villous-like projections in the adult. Regardless of age, they were invariably covered by a prominent external lamina, and mutually interdigitated with connectivetissue elements in the adjacent tendon. Various stages of myofibrillar assembly and sarcomere alignment were evident in the muscle fiber terminus at birth. With advancing age, splitting of terminal sarcomeres at Z bands commonly gave rise to diverging myofilament bundles that attached to electron-dense patches under the sarcolemma. In these regions, leptomeric organelles were also encountered in neonatal and adolescent myotendons. At all stages, the ends of muscle fibers possessed cytological features consistent with active synthesis and secretion. Densely-packed sarcoplasmic organelles including multiple Golgi complexes, clusters of ribosomes, mitochondria, cytoplasmic vesicles, and elements of rough- and smooth-surfaced endoplasmic reticulum were prevalent. Peripheral and centrally-placed heterochromatic nuclei with prominent nucleoli were arranged singly or in groups at the ends of muscle fibers. Satellite cell profiles and unmyelinated axons in the subjacent tendon were also identified at these sites in the adult. Fibroblasts in growing tendon were plentiful, and at all stages, possessed morphological features indicative of high metabolic and secretory activities.
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  • 32
    ISSN: 1432-0533
    Keywords: Neuronal ceroid-lipofuscinosis ; Membranous cytoplasmic body ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An autopsy case of adult neuronal ceroid-lipofuscinosis was examined. The clinical picture was charaterized by gait disturbance, bulbar palsy and dementia. Histopathologically, diffuse neuronal loss was found throughout the central nervous system. The remaining neurons, predominantly in the motor nuclei of the spinal cord and brain stem, were swollen with storage material. Observed under the electron microscope the storage material showed various ultrastructures, such as lipofuscin-like bodies, pleomorphic lipid bodies, curvilinear profiles and finger-print profiles, in different regions of the central nervous system. In the ballooned neurons of the spinal anterior horn, many membranous cytoplasmic bodies and curvilinear profiles were intermingled within the same cell and were continuous with each other. Biochemically,N-acetyl neuraminic acid content was significantly increased in the spinal anterior horn. These findings suggest the localized increase of ganglioside in that region.
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  • 33
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    Archives of microbiology 148 (1987), S. 150-154 
    ISSN: 1432-072X
    Keywords: Bacteroides ; Vesicles ; Ultrastructure ; Cellulolytic bacteria ; Rumen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In 3-day-old cultures of Bacteroides succinogenes grown on filter paper, no cell division was observed. When grown on cellulosic substrate, bacteria exhibited vesicles clustered within cell wall pockets. In 2 day-old filter paper cultures, cells adhered tightly to the substrate. Twenty to 30% of them were dividing. There were cell wall pockets in about 25% of the bacteria, but no vesicles. Whether they adhered to the cellulosic substrate or not, and irrespective of the age of the bacteria, storage polysaccharides were found in the form of dense granules in the cytoplasm. It would appear that vesicles are not essential for cellulose degradation, but are rather a sign of ageing of the cells.
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  • 34
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    Archives of dermatological research 279 (1987), S. 173-179 
    ISSN: 1432-069X
    Keywords: UV-A pigmentation ; Ultrastructure ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary UV-A-induced skin pigmentation was investigated morphologically in semithin and thin sections from 11 volunteers, using different irradiation modalities (single doses of 10,50 and 100 J/cm2). Visible skin pigmentation was observed in all but two probands, and erythema in two; pronounced pigmentation was present after repeated irradiation only. Contralateral non-irradiated, UV-B-irradiated and suntanned skin specimens were used as controls. There was an increase in the number of clear cells in the basal layer (x 1.6) and particularly of large clear cells (x 1.7) after repeated irradiation. Also, the number of melanosomes in melanocytic dendrites (x 2.8) increased after repeated irradiation. The number, size and shape of the melanosome complexes in both basal and suprabasal keratinocytes remained unchanged, even when a distinction was made between central and peripheral location. In contrast, suntanned skin showed an increase in melanosome complexes in basal (x 5.8) and suprabasal (x 3.7) keratinocytes. It is concluded that UV-A-induced skin pigmentation differs in some ways from UV-B or sun-induced melanogenesis, and that the clinical grade of tanning cannot accurately be determined by ultrastructural methods.
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    Experimental brain research 67 (1987), S. 41-51 
    ISSN: 1432-1106
    Keywords: Trauma ; Neuron ; Culture ; Calcium ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cultured mouse spinal neurons were fixed at three different intervals after dendrite amputation: within the first 15 min, at 2 h and at 24 h. Dendrites were amputated at lesion distance of either 50 μm (31% probability of cell survival) or 100 μm (53% probability of cell survival) from the edge of their perikarya. When fixed within 15 min, operated neurons showed a two-phase gradient of ultrastructural damage which spread from the transection site towards the perikaryon. At 2 h after dendrite amputation all neurons operated close to their perikarya were categorized as either viable, moribund or dead, based on their appearance with phase contrast microscopy. These categories of response to physical trauma corresponded to distinctly different ultrastructural changes. Moribund neurons were filled with membrane-bound vesicles which were derived from swollen mitochondria and grossly dilated cisternae of the smooth endoplasmic reticulum. The cytoplasm of dead neurons contained large clear areas and many condensed, dark mitochondria. Both moribund and dead neurons lacked cytoskeletal elements. All of these ultrastructural changes are hypothesized to be the result of an increase in the intracellular concentrations of free calcium. Although evidence of residual mitochondrial swelling was present in some surviving neurons at 24 h, the ultrastructure of others was comparable to that of control cells. Some surviving neurons had terminal swellings at the ends of the severed neurites which were very similar to retraction balls of transected axons after CNS trauma.
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  • 36
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    Development genes and evolution 196 (1987), S. 367-371 
    ISSN: 1432-041X
    Keywords: Vitellogenesis ; Bufo marinus oocyte ; Yolk-platelet membrane ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Oocytes of the toad Bufo marinus have been studied by means of thin section and particularly freeze-fracture electron microscopy to characterize the cytoplasmic membranes around the yolk organelle, and the storage of yolk material in precursors and platelets. This appears to be a previously unknown type of yolk-platelet formation. During yolk-organelle development from the primordial precursor to the bi-partite fully grown yolk platelet, numerous lipoid droplets are attached to the periphery of the platelet, indicating an intense uptake of lipids. As is typical for amphibians, the fully grown yolk platelet has a crystalline internum covered by a dense osmiophilic externum, and the whole organelle is enveloped by a plasma membrane that shows no direct connection or fusion with endocytotic vesicles. The yolk membrane exhibits few intramembraneous particles (IMPs) at the core areas and some more where it borders fields of lipoid droplets. Here the IMPs show a net-like arrangement in the furrows between adjacent droplets.
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    Theoretical and applied genetics 74 (1987), S. 177-187 
    ISSN: 1432-2242
    Keywords: Barley ; Grain development ; Mutants ; Ultrastructure ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Eleven Na-azide induced barley shrunken endosperm mutants expressing xenia (sex) were characterized genetically and histologically. All mutants have reduced kernel size with kernel weights ranging from 11 to 57% of the wild type. With one exception, the mutant phenotypes are ascribable to single recessive mutant alleles, giving rise to a ratio of 3∶1 of normal and shrunken kernels on heterozygous plants. One mutant (B10), also monofactorially inherited, shows a gene dosage dependent pattern of expression in the endosperm. Among the 8 mutants tested for allelism, no allelic mutant genes were discovered. By means of translocation mapping, the mutant gene of B10 was localized to the short arm of chromosome 7, and that of B9 to the short arm of chromosome 1. Based on microscopy studies, the mutant kernel phenotypes fall into three classes, viz. mutants with both endosperm and embryo affected and with a non-viable embryo, mutants with both endosperm and embryo affected and with a viable embryo giving rise to plants with a clearly mutant phenotype, and finally mutants with only the endosperm affected and with a normal embryo giving rise to plants with normal phenotype. The mutant collection covers mutations in genes participating in all of the developmental phases of the endosperm, i.e. the passage from syncytial to the cellular endosperm, total lack of aleurone cell formation and disturbance in the pattern of aleurone cell formation. In the starchy endosperm, varying degrees of cell differentiation occur, ranging from slight deviations from wild type to complete loss of starchy endosperm traits. In the embryo, blocks in the major developmental phases are represented in the mutant collection, including arrest at the proembryo stage, continued cell divisions but no differentiation, and embryos deviating only slightly from the wild type.
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  • 38
    ISSN: 1432-0533
    Keywords: Cerebellum ; Histogenesis ; Cisdichlorodiammineplatinum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this electron microscopy study was to further investigate the effects of cis-dichlorodiammineplatinum (cis-DDP) on the cerebellum of the immature rat. Ten-day-old animals were treated with cis-DDP subcutaneously and killed after 1, 7, 15 or 21 days. On postinjection day 1, cis-DDP effects were evident mainly in the external granular layer, with nuclear damage in many dividing cells, while their cytoplasm appeared to be less affected. Some binucleate cells were also present. On the contrary, in postmitotic or more differentiated cells, only cytoplasmic alterations were found. At later stages (postinjection day 7), the frequency of damaged cells in the external granular layer decreased, but there was a cellular deficit in the internal granular layer. Many postmitotic neurons underwent coagulative necrosis. Finally (postinjection days 15 and 21), the cellular deficit was partly compensated for by “reactive” structures, e.g., glial cell fibers, which underwent hypertrophy after initial edema. Moreover, packing densities of Bergmann astrocytes and oligodendrocytes were higher.
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  • 39
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    Acta neuropathologica 73 (1987), S. 92-98 
    ISSN: 1432-0533
    Keywords: Spinal gliomas ; Vascular proliferation ; Ethylnitrosourea ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The histology and ultrastructure of ten spinal cord gliomas, mainly oligodendrogliomas, induced transplacentally in rat with ethylnitrosourea were studied. The characteristic feature of seven spinal tumours was distinct delineation of neoplastic tissue from the edematous surrounding zone by a ring of irregular, proliferating capillaries, among which immature capillary buds prevailed. The alterations were proliferation of endothelium with endothelial overlapping, elongation of interendothelial junctions and enhancement of pinocytotic vesicles on luminal and abluminal surfaces. The basal membranes, besides other changes, were often replaced by some floccular condensations. In the edematous zone the capillary walls were deprived of contact with glial processes. The lack of contact between astrocytic processes and vascular wall may contribute to the persistent immature state of peripheral capillaries.
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    Archives of gynecology and obstetrics 240 (1987), S. 33-43 
    ISSN: 1432-0711
    Keywords: Ovary ; Surface epithelium ; Perfusion ; Rabbit ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using transmission electron microscopy we examined the morphology of the surface epithelium of the isolated and perfused rabbit ovary after an ovulatory dose of HCG. Rupture of follicles occurred in vitro approximately 13 h after HCG-injection and 6 h after the start of perfusion. The ultrastructural changes during the perfusion were similar to those occurring in vivo. The perfused ovarian epithelium had villous processes of varied architectural complexity with squamoid and cuboid epithelial cells. The superficial cells contained pinocytotic vesicles, coated and noncoated endocytotic caveolae, and occasional vacuoles. Dense bodies were more commonly found in vitro than in vivo. Occasionally structures similar to “Call-Exner-bodies” were found on the surface epithelium near to preovulatory follicles. Intercellular spaces of various sizes were also numerous. Disappearance of surface epithelium in the apex of follicles was often observed and the matrix of the tunica albuginea consisted of dissociated fibers and degenerating cells. This study showed that the isolated perfused rabbit ovary can serve as a model for studying the biology and pathology of ovarian surface epithelium.
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  • 41
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    European journal of epidemiology 3 (1987), S. 187-195 
    ISSN: 1573-7284
    Keywords: Human intestinal spirochetes ; Swine intestinal treponemes ; T. hyodysenteriae ; T. innocens ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ultrastructure of twenty human intestinal spirochetes was analyzed using the electron microscope. Negatively stained cells were generally found to be loosely and irregularly waved. The isolates had cell dimensions ranging from 0.12–0.35 μm in width and from 3.9–14.2 μm in length. Twin bundles of flagella were present in the space between the cytoplasmic membrane and the outer membrane. The majority of isolates had five flagella inserted sub-terminally at each cell end. Human intestinal spirochetes divide by binary fission. They are morphologically similar to swine intestinal treponemes, both pathogenic (Treponema hyodysenteriae) and non pathogenic (Treponema innocens), and different from Treponema pallidum, Treponema phagedenis and Borrelia burgdorferi. Following treatment with sodium deoxycolate, no bundles of cytoplasmic microtubules were observed in cells obtained from cultures of human and swine intestinal spirochetes or from cells of B. burgdorferi, while these structures were present in similarly treated cells of T. pallidum and T. phagedenis.
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    Protoplasma 137 (1987), S. 45-55 
    ISSN: 1615-6102
    Keywords: Carbohydrates ; Chilling effects ; Populus ; Sugars ; Ultrastructure ; Xylem ray cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of xylem ray cells inPopulus was studied in conjunction with their content of individual sugars and of starch. They differ considerably in structure and in carbohydrate content at the three chosen stages,i.e., of starch deposition (August), of starch maximum (November), and of starch dissolution (January). The transition from the summer to winter stage was also induced experimentally by storage of tissue at 0°C. Both in nature and after cold-storage, sucrose and its galactosides raffinose and stachyose were accumulated to a great extent, contributing up to 69.7 and 57.3% of total sugar content, respectively. They originated parallel to the breakdown of starch and to the appearance of abundant vesicular and dilated ER cisternae. Results indicating that they are the specific sites of sucrose accumulation, and/or its galactosides, are discussed. The occurrence of phytoferritin-like crystalloids in amyloplasts and of vacuolar flocculent material, which condenses into electron-dense bodies of suspectedly proteinaceous nature, is described.
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  • 43
    ISSN: 1615-6102
    Keywords: Alkaloid production ; Catharanthus roseus ; Plant cell culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Periwinkle (Catharanthus roseus) cells cultured in 1-B 5 medium display the ultrastructure of parenchyma cells. The parenchyma character remained unchanged when cells were exposed to any one of three different conditions effecting alkaloid accumulation. Transfer of cells to “alkaloid production medium” for 2 weeks (condition 1) accorded two special features,i.e., unusually big lipid droplets in the cytoplasm and, upon fixation, one or several electron-dense droplets of spongy precipitate in vacuoles. Among hormone-autotrophic cultures (condition 2) some cells showed a fine electron-dense vacuolar precipitate. Addition ofPhythium homogenate (fungal elicitor) to cells cultured in 1-B 5-medium for 10 days (condition 3), cells showed a frequent appearance of singular big lipid droplets in the cytoplasm, whereas vacuoles remained devoid of precipitate. The appearance of big lipid droplets and of vacuolar precipitate is interpreted as progressing cytodifferentiation, but is coincidental with alkaloid accumulation.
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  • 44
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    Protoplasma 137 (1987), S. 71-83 
    ISSN: 1615-6102
    Keywords: Alisma ; Embryogenesis ; Endopolyploidy ; Suspensor differentiation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of the suspensor (consisting of a basal cell and a few chalazal cells) inAlisma plantagoaquatica andA. lanceolatum was investigated using cytochemical methods, light and electron microscopy. The basal cell becomes differentiated during the first three days of embryo development. As a result of endopolyploidization the volume of the nucleus rapidly increases, as does the quantity of chromatin it contains and the size of the nucleolus. As basal cell grows, its cytoplasm increases in volume and the number of organelles increase, and wall ingrowths begin to form on the walls at the micropylar pole of the cell. The full development and functioning of the suspensor occurs during the next three days. The enormous basal cell then attains its maximum degree of differentiation: its nucleus reaches a ploidy of 256n or 512n, the micropylar transfer wall is fully developed, as is the cytoplasm, rich in proteins, ribonucleic acids (RNA) and organelles, particularly dictyosomes and long cisternae of the rough endoplasmic reticulum. The chalazal suspensor cells joining the embryo proper to the basal cell also become differentiated. In the seven-day embryo the suspensor begins to degenerate which coincides with the cellularization of the endosperm at the micropylar pole of the embryo sac. The senescence of the suspensor involves the degradation of the nucleus, increasing cytoplasmic vacuolization, and a distinct decrease in protein and RNA content, first in the basal cell, then in the chalazal suspensor cells. Analysis of the development and ultrastructure of the basal suspensor cell suggests that it plays the role of an active metabolic transfer cell, translocating nutrients from the maternal tissues via the chalazal suspensor cells to the growing embryo proper.
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987) 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 46
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. i 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 47
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amino acids can be identified unambiguously in form of their dansylated methyl esters by combination of thin-layer chromatography on polyamide and subsequent mass spectrometry without prior substance elution from the chromatographic polyamide carrier. The evaporation intensity of the amino acid derivatives is sufficient to get excellent mass spectra with significant structural information also with very small amounts of starting material (picomole level), which guarantee a high separation power in the TLC step. Besides the methylester derivatives, in part, products additionally methyl substituted at the sulfonamide nitrogen could be separated.
    Additional Material: 1 Tab.
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  • 48
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The simple combination of thin-layer chromatography on polyamide with subsequent mass spectrometry of the separated compounds together with the carrier material has been employed for unambiguous identification of individual dipeptides in a mixture. The dipeptides were analysed in the form of their dansyl methyl ester derivatives. The appearance of molecular ions in the electron impact mass spectra simultaneously with the ions dans-NH=CHR⌝+ indicating the corresponding N-terminal amino acid residue enables a rapid and sensitive structure elucidation of the dipeptides. The chromatography and mass spectrometry can be performed with 0.2-0.3 nmol dipeptide.
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  • 49
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    Biological Mass Spectrometry 14 (1987), S. 357-362 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several classes of environmentally significant compounds were introduced into an ion trap detector (ITD) by capillary column gas chromatography, and the performance of the device as a gas chromatography/mass spectrometry (GC/MS) system was studied. The experiments conducted included studies of the precision of selected ion monitoring (SIM) measurements, the precision of relative ion abundance measurements in full mass range scans, the sensitivity and instrument detection limits in SIM and full mass range data acquisition, and the linear range of concentration calibration. It was observed that resolution may be lost and saturation may occur under certain conditions, and that the data system can report artifact ions under these conditions.
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  • 50
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Brominated dioxins and dibenzofurans (PBDDs and PBDFs) are known contaminants in commercial fire retardant preparations. Further, they are formed in incineration processes involving polybrominated biphenyl and diphenylether fire retardants. This report presents the characterization of polybrominated dioxins and dibenzofurans. In particular, environmental monitoring methodology for PBDDs and PBDFs has been developed, and confirmation criteria for GC/MS analyses are presented.
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  • 51
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    Biological Mass Spectrometry 14 (1987), S. 473-477 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Analysis of reports in the world's literature suggests that average sperm densities for groups of unselected males were relatively constant at about 108 million cells per ml prior to 1950. Subsequent to that time mean sperm densities appear to have declined. Regression analysis indicates the existence of significant negative correlations between mean sperm densities and production of synthetic organic chemicals among other parameters. Phthalate esters are one class of large volume organic chemicals that are known to disturb testicular function in laboratory animals. These compounds are also the most abundant man-made chemicals in the environment. Plots of the concentration of dibutylphthalate in the cellular fraction of ejaculates against either the sperm density or the total number of sperm for the same ejaculates gave two clusters of points. These clusters suggest the existence of two or more populations vis à vis phthalate metabolism; both of which show a negative correlation between phthalate concentration and sperm production.
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  • 52
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    Biological Mass Spectrometry 14 (1987), S. 481-485 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We report a case of n-nonacosane storage disease, which went undiagnosed until the death of a 55-year-old farmer. Clinical, histological, and biochemical features are discussed. n-Nonacosane storage was identified by gas chromato-graphic-mass spectrometric analysis of different tissue extracts, n-nonacosane concentration reaching 1.2 mg g-1 of lung tissue and 0.32 mg g-1 of liver tissue. It was possible to rule out a work-induced intoxication, and n-nonacosane storage appeared to be accounted for by a lifelong, heavy consumption of unpeeled apples and Brussels sprouts.
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  • 53
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new technique known as thermally-assisted fast atom bombardment (TA-FAB) has been applied to the analysis of a series of cyclic tetrapeptide mycotoxins in order to demonstrate the usefulness of the method for structural elucidation. TA-FAB uses saturated aqueous solutions of highly hydroxylated compounds, such as fructose, as alternatives to the usual viscous liquid matrices employed in conventional FAB. During the TA-FAB analysis, the probe tip is resistively heated causing diffeiences to occur in the desorption profiles for the analyte and the matrix ions enabling an optimization for analyte desorption as a function of temperature. In this study, direct comparisons are made between TA-FAB, conventional FAB, and electron impact ionization for the analysis of the Helminthosporium carbonum mycotoxins at the 1.5 μg level. The results demonstrate the superior capacity of TA-FAB to provide both molecular weight confirmation and significant fragmentation to aid in the structural elucidation of these important biomolecules.
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  • 54
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    Biological Mass Spectrometry 14 (1987), S. 517-521 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three glutathione conjugates of acetaminophen were characterized by fast atom bombardment/mass spectrometry (FAB/MS) and fast atom bombardment/mass spectrometry/mass spectrometry (FAB/MS/MS). The conjugates, 3-(glutathion-S-yl)acetaminophen, 3-(glutathion-S-yl)diacetaminophen and 3-(diglutathion-S-yl)diacetaminophen showed intense [MH]+ ions at m/z 457, 606 and 911, respectively. Only 3-(glutathion-S-yl)acetaminophen showed any fragmentation by FAB/MS. Structurally characteristic fragmentation was observed with all three conjugates when the [MH]+ ions were collisionally activated. The loss of the glycine (GLY) and glutamic acid (GLU) moieties indicated the presence of at least one glutathione (GSH) group. Multiple losses, some of which could only occur via cleavages in both GSH moieties, were observed with the diglutathione conjugate.
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  • 55
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    Biological Mass Spectrometry 14 (1987), S. 549-553 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A GC-MS procedure has been developed for the quantitation in plasma and urine of rimantadine, an antiviral drug effective against type A influenza. The assay utilizes selective ion monitoring, methane negative ion chemical ionization (NCI) and stable isotope dilution. Sensitivity to NCI is effected by derivation of rimantadine with pentafluorobenzoyl chloride. The method has been used to quantitate plasma concentrations of rimantadine over a range from 4.2 ng/ml to 416 ng/ml, and urinary concentrations of rimantadine over a range of 21 ng/ml to 2077 ng/ml.
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  • 56
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    Biological Mass Spectrometry 14 (1987), S. 127-129 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described to assign the positional series of methylene interrupted polyenoic acids, in complex mixtures, isolated from hydrolysed lipid extracts. It entails a simple comparison of the intensities of three ions of m/z 108, 150 and 192.
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  • 57
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The behaviour of 1,1·,1″-phosphinothioylidinetrisaziridine (thiotepa) in water and aqueous salt solution of various acidity was studied by field ionization mass spectrometry (FI-MS), TLC and potentiometric titration. The rate of thiotepa hydrolysis increased with increasing thiotepa, or sodium chloride concentration, and with decreasing pH. As hydrolysis products of thiotepa, mono- and dichloro derivatives formed in neutral, salt-containing and acidic solution, tepa, and products formed by P—N bond cleavage and release of aziridine have been identified.
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  • 58
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methodology for the qualitative and quantitative analysis of the anthelmintic fenbendazole and its metabolites in goat feces using electron impact (EI)/direct exposure probe (DEP)/mass spectrometric (MS) and tandem mass spectrometric (MS/MS) techniques is presented. Analyses were conducted on extracts from spiked feces and feces from animals treated per os with 5 mg fenbendazole/kg, with samples being collected at zero time and at twelve hour intervals for 144 h. The results of the EI/DEP/MS quantitation of these samples are compared to those for the same samples analysed by high pressure liquid chromatography (HPLC). Mass spectral data for fenbendazole and its metabolites are presented and the advantages of the use of EI/DEP/MS and/or DEP/MS/MS over HPLC are discussed. This methodology may be used as a confirmatory method for the HPLC analysis of fenbendazole and its metabolites or may be used as a method in its own right for the rapid qualitative and quantitative analysis of these compounds.
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  • 59
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Known and possible phenolic and primary and secondary amine metabolites of lidocaine were added to urine from drug-naive rats. These metabolites were derivatized in this aqueous medium by acetylation with acetic anhydride or by pentafluorobenzoylation with pentafluorobenzoyl chloride. The derivatives were simultaneously extracted into an organic solvent. The products were separated by gas chromatography (flame ionization detection for acetates and electron-capture detection for pentafluorobenzoates) and identified by combined gas chromatography/mass spectrometry. Mass spectral fragmentation pathways were readily deduced; diagnostic fragment ions were identified and were valuable for characterization purposes. Structural isomers could be distinguished on the basis of their GC retention times.Extractive derivatization using pentafluorobenzoyl chloride is an attractive analytical procedure for the identification of phenolic and dealkylated metabolites of lidocaine.
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  • 60
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 61
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    Biological Mass Spectrometry 14 (1987), S. 213-220 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermospray HPLC/MS analysis of the metabolites of arachidonic acid proved to be sensitive and specific. The compounds included were hydroxy-fatty acids (5-HETE, 12-HETE, and 15-HETE) and prostaglandins PGD2, PGE2, PGF2α, PGA2, PGA1, TXB2, and 6-Keto-PGF1α. Thermospray HPLC/MS analysis allows for simultaneous monitoring of each compound without the need for additional sample preparation or derivatization. The thermospray spectra for the metabolites exhibited [M + NH4]+ ions and fragment ions because of sequential loss of equivalents of H2O. HPLC/MS showed detection limits in the 0.5 to 5 ng range when using multiple ion detection for most of the metabolites. Post-column derivatization of these metabolites using trimethylanilinium hydroxide (TMAH) to form the methyl esters is also presented. This derivatization resulted in a gain in ion current by a factor of 3-6 for most compounds while adding potential specificity to the analysis. The thermospray spectra of the derivatives were nearly identical to the spectra of the free acid except the peaks were incremented by 14 daltons due to the methyl ester formation. The derivatization of the carboxylic acid group proved to be complete under thermospray conditions producing the maximum ion current and causing no compromise in operation of the interface.
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  • 62
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    Biological Mass Spectrometry 14 (1987), S. 649-651 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The identified urinary metabolites of male rats exposed to indan are: 1- and 2-indanone; 1-, 2- and 5-indanol; 2-and 3-hydroxyl-1-indanone; and cis- and trans-indan-1,2-diol. Indan causes kidney damage in male rats in a manner similar to the cyclic hydrocarbons cis- and trans-decalin and JP-10. Lesions produced by indan occur only in male rats and not in female or control rats.
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  • 63
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dinucleoside monophosphates bearing usual protecting groups at the exocyclic amino functions of the heterocyclic bases, the 5′-hydroxy group, the phosphate moiety and the O-6-position of the guanine ring have been analysed by FAB mass specrometry in the negative ion mode. These non-charged key intermediates for oligodeoxynucleotide synthesis exhibit very simple spectra in the mass range of m/z 400-1500 using tetra-ethylene glycol as matrix. Most of the observed ions could easily be assigned. Apart from deprotonated molecular ions sequence specific ions arising from C-O-P bond cleavage and ions derived from loss of protecting groups were observed. The simplicity of spectra interpretation makes FAB mass spectrometry to a rapid and valuable tool for unambiguous identification of dimeric synthons for oligonucleotide synthesis.
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  • 64
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    Biological Mass Spectrometry 14 (1987), S. 141-142 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 65
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    Biological Mass Spectrometry 14 (1987), S. 131-140 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mixtures of both synthetic and naturally occurring (human plasma) cholesteryl esters have been examined by capillary gas chromatography/mass spectrometry (GC/MS). A magnetic sector mass spectrometer was used and a variety of ionization modes were assessed with a view to obtaining structural information on intact cholesteryl esters. By employing ammonia as reagent gas, with negative ion scanning, spectra were produced from which the nature of steryl and fatty acyl moieties could be readily deduced. Analyses were performed at an ion source temperature of 300°C in order to maintain the integrity of the gas chromatographic profile. The technique described is of general use for the GC/MS analysis of steryl esters, particularly in conjunction with magnetic sector instruments.
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  • 66
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermospray spectra on a magnetic sector mass spectrometer, by definition measured at high accelerating voltages, are seen to be highly fragmented. This is rationalised in terms of the necessity to accelerate ions through a region of high pressure in the vicinity of the ion-collecting orifice at the spray volume, where ions may be energized by ion molecule collisions. In this region, a high percentage of the parent ion current is lost through the dispersion of the ion beam and by the collisional activation of molecular ions resulting in extensive fragmentation. The investigation of means by which these effects may be minimized has led to the construction of an improved sector thermospray source. Comparative results for gramicidin S demonstrate that its fragmentation is reduced and that the intensity of the protonated molecular ion is greatly enhanced.
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  • 67
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    Biological Mass Spectrometry 14 (1987), S. 183-185 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Acetates of 12 positionally isomeric tetradecenols (Δ2-Δ13) have been prepared and their mass spectra measured without any prior chemical modification. Comparison of spectra of all the isomers has shown the variation in intensities of some predominant fragments with the position of the double bond on the 14 carbons chain. The mass spectra were interpreted in terms of the relative intensity ratio of the fragment ion peaks to locate the double bond positions. A procedure for elucidation of the positional isomerism of tetradecenyl acetates is given.
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  • 68
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    Biological Mass Spectrometry 14 (1987) 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 69
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    Biological Mass Spectrometry 14 (1987), S. 207-211 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eight normal subjects ingested 125 mg of p-tyramine-β,β-2H2 hydrochloride and the 3 h and following 21 h urine collections were analysed by mass spectrometry with selected ion monitoring for the deuterated metabolites: free and conjugated p-tyramine-β,β-2H2, free p-octopamine-β-2H1, free and conjugated p-hydroxyphenylacetic acid-α-2H1 and -α,α-2H2, and free p-hydroxymandelic acid-α-2H1. These metabolites accounted for 72% of the ingested label, of which conjugated p-tyramine and free p-hydroxyphenylacetic acid constituted 90%. Approximately 50% of the total deuterated tyramine and 70% of the total deuterated p-hydroxyphenylacetic acid were excreted in the first three hours, although there was considerable variation between individuals. The presence of a small amount of p-hydroxyphenylacetic acid-α-2H1 suggests that some exchange of deuterium occurred at the intermediate p-hydrophenylacetaldehyde stage.These results, based as they are on metabolites labelled with the stable isotope deuterium, ought to be more reliable than earlier studies in which unlabelled tyramine was ingested with the resultant metabolites, indistinguishable from their endogenous metabolic counterparts, being measured by fluorimetry or gas chromatography.
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  • 70
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    Biological Mass Spectrometry 14 (1987), S. 221-227 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Human exposure to aromatic amines may be monitored by measuring the amount of sulfinamide adduct bound to hemoglobin. In order to develop a sensitive and selective method for measuring aromatic amines present in low concentrations the mass spectra of the pentafluoropropionamide derivatives of a series of aromatic amines were determined under various ionization conditions. With electron ionization the aromatic amine derivatives typically yield intense molecular ions with fragmentation leading to elimination of C2F5 and COC2F5. Higher molecular weight polycyclic aromatic amines, e.g., 6-aminochrysene, give prominent molecular ions as well as intense ions corresponding to M-174 (loss of CNHCOC2F5). With positive chemical ionization using methane as reagent gas the derivatives give protonated molecular ions as the base peaks, as well as the associated ions at M + 29 and M + 41. Negative ion chemical ionization yields, primarily, peaks corresponding to the loss of HF from the molecular anions. Negative ion chemical ionization with selected ion monitoring is generally more suitable than positive chemical ionization or electron ionization for the quantitative analysis of aromatic amines present in biological samples in the mid femtomolar range. Exposure of human subjects to aromatic amines was determined via basic hydrolysis of the isolated sulfinic acid amide hemoglobin adducts. Analysis of the derivatized extracts by gas chromatography/negative ion chemical ionization/mass spectrometry demonstrated the presence of aniline, ortho-, meta-, and para-toluidine, 2-naphthylamine, and 4-aminobiphenyl. The hemoglobin adduct levels of these amines in both cigarette smokers and nonsmokers were determined. The mean values of the adduct levels of ortho- and para-toluidine, 2-naphthylamine, and 4-aminobiphenyl were higher in smokers than in nonsmokers, while the mean adduct values of aniline and meta-toluidine were similar in both groups. Adducts of 2-, 3-, 4-ethylaniline, 2,3-, 2,4-, 2,5-, 2,6-dimethylaniline, and 3-aminobiphenyl have been detected in smokers' blood. 1-Aminoanthracene, 9-aminophenanthrene, and 6-aminochrysene have not been detected. GC/MS procedures were also used to determine the extent of binding of aniline-2,3,4,5,6-d5 to hemoglobin in rats administered aniline-d5.
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    Biological Mass Spectrometry 14 (1987), S. 479-479 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 72
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The single dose pharmacokinetics of deuterium-labelled cannabinol (2H2-CBN) were evaluated in six male cannabis users with different degree of abuse after smoking an average dose of 19 mg and after intravenous administration of 20 mg CBN. Plasma levels were measured for up to 72 h with selected ion monitoring by GC/MS using 2H7-CBN as internal standard. The systemic availability of smoked CBN was found to be 39 ± 26% (min-max 6-65%). The mean plasma clearance was 19.1 ± 2.6 ml min-1 kg-1 and the volume of distribution was determined to 50 ± 23 1 kg-1. The apparent terminal half lives for CBN were 32 ± 17 h and 43 ± 29 h after intravenous administration and smoking, respectively.
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    Biological Mass Spectrometry 14 (1987), S. 533-534 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Biological Mass Spectrometry 14 (1987), S. 523-531 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Derivatization of prostaglandins and thromboxane B2 using diethyl amino ethyl chloride and diethyl amino ethyl bromide improved thermospray HPLC/MS sensitivity. The derivatization was evaluated for prostaglandin A1, A2, D2, E2, F1α, F2α, and thromboxane B2. The derivatization reaction, thermospray operating conditions, and mode of detection were optimized to produce the most intense [M + H]+ or [M - H]- ions for the derivative. Derivatization was better than 99% complete in 1 hour at 75°C. No thermal degradation of the prostaglandins was observed. Positive thermospray ionization proved the mode most sensitive, enabling detection from 10 to 300 pg of each prostaglandin under multiple ion detection. The thermospray spectra exhibited intense [M + H]+ ions for the derivative with a few fragment ions from sequential losses of water from the [M + H]+ ion. Detection of a prostaglandin metabolite in plasma over the concentration range from 3 ppm to 30 ppb was possible using this derivatization.
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  • 75
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The gas chromatographic and mass spectrometric properties of leukotriene B4, 20-hydroxy-leukotriene B4 and 20-carboxy-leukotriene-B4 were investigated as their methyl ester trimethylsilyl, methyl ester allyldimethylsilyl and methyl ester tert-butyldimethylsilyl ethers. The gas chromatographic properties of the trimethylsilyl and tert-butyldimethylsilyl ether derivatives were good with respect to peak shape and sensitivity, whereas the allyldimethylsilyl ether derivative gave a lower sensitivity. The sensitivity defined as the quantity that could be passed through the gas chromatographic column.The three derivatives showed a mass spectrometric fragmentation pattern with cleavage of the C12—C13 bond as an important feature. Particularly, the allyldimethylsilyl ether derivative of the three compounds studied exhibited a high tendency for C12—C13 bond cleavage resulting in a fairly intense ion at m/z 435. However, the mass spectra indicated multiple fragmentation pathways due to the presence of double bonds, leading to decreased intensities of the high mass ions. A quantitative analysis by selected ion monitoring of the most intense high mass ions in the respective mass spectrum demonstrated that neither derivative would allow measurements in the low picogram range. Catalytic hydrogenation of the double bonds was performed and the methyl ester trimethylsiyl, methyl ester allyldimethylsilyl and methyl ester tert-butyldimethylsilyl ether derivatives of the reduced compounds were prepared. Saturation of the double bonds increased the gas chromatographic sensitivity for the three derivatives as well as the intensities of the high mass ions in their mass spectra. The high sensitivity that can be obtained by measurement of such high mass ions was demonstrated by quantification of leukotriene B4 in lung tissue samples by selected ion monitoring.
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    Biological Mass Spectrometry 14 (1987), S. 355-355 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Biological Mass Spectrometry 14 (1987), S. 363-367 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The indoor air quality of the offices of smokers and nonsmokers was surveyed for volatile organic compound identities and concentrations. These results were examined to determine whether environmental tobacco smoke contamination could be distinguished from airborne pollutants outgassing from other sources. It was not possible to positively attribute volatile organic contaminants to environmental tobacco smoke. It was possible to distinguish between smokers' and nonsmokers' offices by determining airborne nicotine levels.
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  • 78
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxygen-enhanced negative chemical ionization MS is sensitive and specific for the detection of polychlorinated biphenyls (PCBs) without isobaric interferences (qualitative or quantitative) from congeners of higher levels of chlorination. The collision-induced dissociation (CID) spectra of the [M - Cl + O]- ion of 40 PCB congeners have been acquired on a triple quadrupole mass spectrometer.Qualitative relationships between structure of the congener and its CID spectrum suggest that reliable identification of PCB congeners is possible even where capillary column gas chromatographic separation is incomplete. Congeners with hydrogen atoms located para and meta to the biphenyl linkage show most abundant collision-induced loss of HCl, whereas congeners with a penta-chloro phenyl ring show least CID loss of HCl. Congeners IUPAC 105 and 121 have CID spectra suggesting a pathway for sequential loss of HCl and CO neutrals during the collision-induced dissociation of the [M - Cl + O]- ion of these molecules. Unambiguous identification of PCB congeners in natural materials will require a complete set of pure, synthetic PCB congeners: identification problems are illustrated using an extract of Northern Shark (dogfish) liver oil.
    Additional Material: 4 Ill.
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  • 79
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 535-541 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A moving belt interface was used to identify budesonide metabolites, obtained from rat and mouse liver incubations, by liquid chromatography/mass spectrometry (LC/MS). The metabolites were separated on a small-bore C18 column with an ethanol/water gradient as mobile phase at a flow rate of 0.2 ml min-1. A spray device was used for deposition of the aqueous solvent on to the belt. Chemical ionization mass spectra were obtained with methane as the reagent gas. Deuterium-labelled budesonide, which was used to facilitate metabolite identification by the isotope cluster technqiue, was found to be slightly separated from the unlabelled analogue on the LC column. Incubations were also performed under 18O2 to elucidate the mechanism of a new metabolic pathway (16α, 17α-acetal splitting) and to confirm the oxidative nature of reactions leading to hydroxylated metabolites. The moving belt LC/MS technique afforded higher sensitivity, and gave more abundant MH+ ions of the compounds studied, than previously found by direct probe mass spectrometry. Phthalate ester background, partly from the polymide belt, complicated the identification of minor metabolites.
    Additional Material: 8 Ill.
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  • 80
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    Biological Mass Spectrometry 14 (1987), S. 587-588 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 81
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    Biological Mass Spectrometry 14 (1987), S. 599-602 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for the quantification in plasma of CP-55,940, a new non-opiate oral analgetic agent, using capillary gas chromatography/mass spectrometry. After extraction, derivation of the drug and a structural analog internal standard is carried out with trifluoracetyl imidazole. The derivative exhibited excellent gas chrornatographic properties. Electron impact yielded an abundant high mass ion whose monitoring permitted the sensitive and specific determination of CP-55,940 down to 0.5 ng ml-1.
    Additional Material: 3 Ill.
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  • 82
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    Biological Mass Spectrometry 14 (1987), S. 613-616 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for the quantification of tulobuterol in human plasma, based upon selective extraction and high resolution capillary gas chromatography-mass spectrometry. The mass spectrometric determination is based on selected ion monitoring of two fragment ions derived from the N,O-heptafluorobutyryl derivatives of tulobuterol and its internal standard, deschlorotulobuterol. The plasma work-up procedure consists of extraction of 1.0 ml alkalinised plasma with dichloromethane, back-extraction into an acidified aqueous phase, followed by a final extraction with dichloromethane after realkalinisation. The method gave interference-free and linear results. The between-assay variability is 4.7% CV at the 3.0 μg l-1 plasma concentration level. The assay permitted quantitative measurements down to 170 ng tulobuterol per litre of plasma and hence provided sufficient sensitivity for quantification of plasma levels after therapeutic doses.
    Additional Material: 3 Ill.
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  • 83
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    Biological Mass Spectrometry 14 (1987), S. 627-632 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In phytochemical and chemotaxonomic research work mass spectrometry plays an outstandingly important role. Using gas chromatography/mass spectrometry (GC/MS) we established the chemotaxa of Tanacetum vulgare L. Chemotypes with essential oils countaining 60-90% of artemisia ketone, carveol, dihydrocarvone, myrtenol, umbellulone, terpinen-4-ol, davanone, and Tagetes species containing various essential oils can be clearly distinguished by their spectra; we examined many variations of Tagetes erecta, T. lucida, T. minuta, T. patula and T. tenuifolia. We have identified α-β-pinene-, 1,8-cineol-, linalool-, camphor-, nerol-, geraniol- and γ-gurjonene as components of Achillea distans L. Injecting the essential oil direct from the oil-secreting organs of T. minuta plants we identified using GC/MS 6-10 and 16% eugenol from the involucral bract and hypsophyll, respectively, as well as β-ocimene, dihydrotagetone, tagetone, Z- and E-ocimenones. In the course of studies on essential fatty acids Borago officinalis and Lappula squarrosa were selected from 70 species of the family Boraginaceae to obtain seed oil as a source of γ-linolenic acid, and for the PG synthesis we isolated several grams of γ-linolenic acid, as well as C18:4, i e. octadecatetraenic acid, from L. squarrosa on the basis of the mass spectra. From the seed oil of Aquilegia vulgaris C18:3 (5) from the oil of Limnanthes dougloasii C20:1 (5) and from the seed oils of Delphinium consolida and of Tropaeolum species (T. majus, T. minus, T. peregrinum) C20:1 (11) fatty acids were identified on the basis of spectra.
    Additional Material: 10 Ill.
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  • 84
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bile from rats treated with acetaminophen was analyzed by direct injection onto a thermospray liquid chromatography/mass spectrometry (LC/MS) system. Two conjugated metabolites of acetaminophen were separated by the high-pressure liquid chromatographic system and analyzed by mass spectrometry. The conjugates were identified as the glutathione-acetaminophen conjugate and the glucuronide-acetaminophen conjugate by comparison of the chromatographic retention times and the mass spectra to that of the synthetic standards. No evidence of acetaminophen metabolites was observed when bile samples were subjected to direct analysis by fast atom bombardment mass spectrometry.
    Additional Material: 6 Ill.
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  • 85
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    Biological Mass Spectrometry 14 (1987), S. 733-736 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
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  • 86
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Direct analysis of unpurified urine from patients with β-ketothiolase deficiency and glutaryl-coenzyme A dehydrogenase deficiency was carried out by methylation and fast atom bombardment mass spectrometry. Previously unidentified signals consistent with unusual acylcarnitines were detected. In the former disease, thermospray liquid chromatography/mass spectrometry analysis confirmed the identification of tiglylcarnitine and differentiated it from a biological isomer, 3-methylcrotonylcarnitine. In glutaric aciduria, glutarylcarnitine was confirmed by detection of glutaric acid liberated upon base hydrolysis of a purified acylcarnitine fraction. The discovery of these metabolites suggests that L-carnitine therapy might be beneficial for the enhanced excretion of toxic metabolites that accumulate in patients with these disorders.
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  • 87
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    Journal of Chemometrics 1 (1987) 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 88
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    Journal of Chemometrics 1 (1987), S. 1-2 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 89
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    Journal of Chemometrics 1 (1987), S. 3-6 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 90
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    Journal of Chemometrics 1 (1987), S. 7-18 
    ISSN: 0886-9383
    Keywords: Kalman filter ; Calibration ; Curve resolution ; Parameter estimation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The application of the Kalman filter to the solution of a variety of problems in analytical chemistry is reviewed. Five examples are selected from the literature to illustrate the use of Kalman filtering techniques for obtaining least-squares estimates fo several parameters of analytical importance. These examples include multicomponent curve resolution and concentration estimation, correction for variable background responses, calibration with drift compensation, and estimation of kinetic parameters for first-order reactions and for heterogeneous charge-transfer reactions. An adaptive Kalman filtering technique is required for the solution of the background correction problem, and the extended Kalman filter algorithm is required for the solution of the nonlinear kinetic problems. For each case, the results that were obtained are summarized, and some advantages of Kalman filtering over traditional least-squares approaches are discussed.
    Additional Material: 4 Ill.
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  • 91
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    Journal of Chemometrics 1 (1987), S. 19-31 
    ISSN: 0886-9383
    Keywords: Calibration ; Indirect calibration ; Multivariate ; Matrix decomposition ; PLS ; PCR ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Partial least squares (PLS) modeling is an algorithm for relating one or more dependent variables to two or more independent variables. As a regression procedure it apparently evolved from the method of principal components regression (PCR) using the NIPALS algorithm, which is similar to the power method for determining the eigenvectors and eigenvalues of a matrix. This paper presents a theoretical explanation of the PLS algorithm using singular value decomposition and the power method. The relation of PLS to PCR is demonstrated, and PLS is shown to be one of a continuum of possible solutions of a similar type. These other solutions may give better prediction than either PLS or PCR under appropriate conditions.
    Additional Material: 4 Tab.
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  • 92
    ISSN: 0886-9383
    Keywords: Principal component analysis ; Singular value decomposition ; Factor analysis ; Rank determination ; Eigenvector analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The distribution of error eigenvalues resulting from principal component analysis is deduced by considering the decomposition of an error matrix in which the errors are uniformly distributed. The derived probability function is \documentclass{article}\pagestyle{empty}\begin{document}$$ P(\lambda ^0 _j) = N(r - j + 1)(c - j + 1) $$\end{document} Where λ0j is the jth error eigenvalue, r and c are the numbers of rows and columns in the data matrix, and N is the normalization constant. This expression is tested and validated by investigations involving model data. The distribution function is used to determine the number of factors responsible for various sets of spectroscopic data taken from the chemical literature (including nuclear magnetic resonance, infrared and mass spectra).
    Additional Material: 1 Ill.
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  • 93
    ISSN: 0886-9383
    Keywords: Curve resolution ; Liquid chromatography ; Accuracy ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The performance of curve resolution and iterative target transformation curve resolution in quantitative liquid chromatography with a diode array detector is evaluated. Quantitative accuracy of the elution profiles obtained for two- and three-component mixtures has been evaluated as a function of spectral similarity, chromatographic resolution and ratio of the peak areas, using a number of simulations analysed by an analysis of variance. The results obtained by simulation are compared and validated with the results obtained for the separation of phenylene diamines in reversed phase liquid chromatography and proteins in gel permeation liquid chromatography. The results that were obtained are summarized and the chromatographic implications are discussed.
    Additional Material: 3 Ill.
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  • 94
    ISSN: 0886-9383
    Keywords: Multi-way array ; Multiorder array ; Principal components ; PLS ; Multivariate calibration ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Lohmöller-Wold decomposition of multi-way (three-way, four-way, etc.) data arrays is combined with the non-linear partial least squares (NIPALS) algorithms to provide multi-way solutions of principal components analysis (PCA) and partial least squares modelling in latent variables (PLS).The decomposition of a multi-way array is developed as the product of a score vector and a loading array, where the score vectors have the same properties as those of ordinary two-way PCA and PLS. In image analysis, the array would instead be decomposed as the product of a loading vector and an image score matrix.The resulting methods are equivalent to the method of unfolding a multi-way array to a two-way matrix followed by ordinary PCA or PLS analysis. This automatically proves the eigenvector and least squares properties of the multi-way PCA and PLS methods.The methodology is presented; the algorithms are outlined and illustrated with a small chemical example.
    Additional Material: 5 Ill.
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  • 95
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    Journal of Chemometrics 1 (1987), S. 73-73 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 96
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    Journal of Chemometrics 1 (1987), S. 75-75 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 97
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    Journal of Chemometrics 1 (1987), S. 74-74 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 98
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    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 1 (1987) 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 99
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    Journal of Chemometrics 1 (1987), S. 77-77 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 100
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    Journal of Chemometrics 1 (1987), S. 79-90 
    ISSN: 0886-9383
    Keywords: Numerical deconvolution ; Peak resolution ; Peak separation ; Iterative deconvolution ; Jansson's method ; Super-resolution ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Severely overlapped gas chromatographic peaks can be resolved using Jansson's method. Jansson's method is an iterative nonlinear deconvolution technique and consists of Van Cittert's algorithm with the relaxation factor a function of the kth estimate of the peak shape. The maximum peak amplitude of the instrument and peak non-negativity serve as constraints to improve the peak estimate. Super-resolution is achieved without significantly degrading the chromatogram signal-to-noise ratio. The method only requires a knowledge of the instrument impulse response function and maximum peak height.
    Additional Material: 7 Ill.
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